To prove Theorem REF  we will adapt the approach of
the papers [1]}, [2]}, [3]} (which deal with the
case where \(G\)  is a constant simplicial group) to the case
where \(G\)  is an arbitrary group in \(s{K}/B\) .
An important ingredient in [1]}, [2]}, [3]} is the notion of an
equivariant NDR pair, a notion which we have already explained
(see Section  above)
has a straightforward generalization to the parametrized setting.
